The present invention relates generally to hinges, and more particularly to hinges fabricated using an injection molding process.
At least some known hinges includes three metallic components, i.e. a base element, a swivel hinge, and a hinge pin coupling the base element to the swivel hinge. The three components are molded separately and then assembled to form the hinge.
Another exemplary hinge is fabricated using an injection molding process. To fabricate the hinge, a molding material, such as plastic, is molded under high temperature and pressure. The molding material typically fills-out the mold to form the hinge. The molded hinge includes a swivel element having at least two openings extending therethrough. The molded hinge also includes a base element having a swivel shaft which is journaled for rotation within the two openings. The openings include a plurality of fingers that extend radially around the openings. The radial fingers position the swivel shaft and are also formed as molding gates for molding windows. After the molding process is completed, the radially extending fingers or vestiges are broken to allow the swivel element to rotate with respect to the base element.
While the molded hinge is useful in a variety of applications, the molding process results in increased clearances between the openings and the swivel shaft. More specifically, the molding process causes a small quantity of excess or residual molding material to be deposited in an area defined between the base element openings and the swivel shaft ends. This material is generally referred to as vestiges. After the molding process is completed, the residual molding material or vestiges are “broken” to form the hinge assembly. During operation, the vestiges or fingers function as journals to maintain a position of the swivel shaft within the swivel element. However, since the vestiges are used to position the swivel shaft during operation, additional movement between the swivel element and the base element is introduced between the two elements. As a result, the overall torque which may be applied to the hinge assembly during operation is reduced.
A need remains for a hinge assembly that provides the benefits of a molded hinge, while also increasing the torque which may be applied to the hinge during operation.